1. Field of the Invention
The present invention relates to a sample cell for use in a gas analyzer capable of analyzing various kinds of components contained within a sample gas by utilizing an optical absorption characteristic of the components and, more particularly, to a sample cell construction having improved gas flow.
2. Description of Related Art
Sample cells, provided for use in a gas analyzing system, are capable of analyzing various components contained within a sample gas by radiating the gas with a beam of energy such as infrared radiation. Infrared radiation will pass through the sample cell and the sample gas contained therein from one side of the cell to the other side. An example of a sample cell has been disclosed in Japanese Patent Publication No. Sho 62-3369 and shown, for example, in FIG. 4.
Referring to FIG. 4, the sample cell 11 includes a cell body 12 having an upper gas inlet port 13 provided at one end of the cell body 12, and an upper gas outlet port 14 provided at the other end of the cell body 12. Beam transmitting windows 15a and 15b are mounted at opposite ends of the cell body. A light source 16 can be arranged opposite an entrance window 15a, while a detector 17 can be arranged opposite the exit window 15b, whereby a gas analysis can be performed on a sample gas contained within the cell body.
In operation, a sample gas is introduced into the cell body 12 through the gas inlet port 13, and will flow across the interior of the cell body to exit through the gas outlet port 14. During this process, a beam of suitable radiation is emitted from the light source 16 and is transmitted through the cell body to be incident upon the sensor or detector 17 to provide representative signals that can be analyzed to determine the components within the sample gas.
In operation, the sample gas that is introduced through the gas inlet port 13 will generally reach a steady state operation wherein the main flow of the gas will traverse the shortest distance connecting the gas inlet port 13 with the gas outlet port 14. Remote portions of the cell body 12, such as indicated by the reference letters a and b in FIG. 4, can constitute dead spaces wherein a portion of the sample gas can become stagnant and alter the uniform sampling of the gas specimen. Additionally, a problem can occur in that the displacement of the sample gas within the sample cell body 12 can be delayed and the response speed of the gas analysis can be reduced. The prior art accordingly is still seeking to optimize a sample cell for measuring components in a gas sample.